The Gene Expression Resource has been operational since January 2001 and primarily provides GeneChip technology to researchers at Roswell Park Cancer Institute (RPCI). Since its inception, the Resource has run over 32 different experiments involving more than 400 individual samples. Sottware and training are available to enable researchers to analyze large data sets and obtain meaningful results from these experiments. The goal is to provide RPCI researchers with access to microarray technology and bioinformatics at an affordable cost. The Resource provides training for analysis ofmicroarray data and programs designed to analyze large data sets. Training for real-time quantitative PCR for extension of GeneChip data and validation studies is also available in the Resource. The Gene Expression Resource houses a Transgenomic Wave system that is used for mutation or polymorphism studies on relatively large strands of DNA (100-600 bp). In 2001, RPCI purchased a Pyrosequencing System that is a high-throughput instrument capable of identification and analysis of small nucleotide polymorphisms (SNPs) and mutations in short strands of DNA. Having access to these systems provides investigators with high throughput platforms for researching any type of sequence variation. The study of gene expression and the investigation into the roles of sequence variation in the genome are natural adjuncts to microarray analysis. Over the next project period, the Gene Expression Resource will continue to provide training, support and consultation for investigation into the roles of DNA sequence variation in the genome. This Resource serves the needs of the CCSG Programs in which 88% of users were members and 84% were peer-reviewed. The Strategic Plan of the Resource is to continue to provide state-of-the-art Gene Chip technology to CCSG Program members and to meet regularly with CCSG Program Leaders and members to identify additional needs, with the aim of increased funding and peer-reviewed publications.